Thank you! The first one is good. I tried "netcat examples" and so on..



I worked out a solution for my task (script that behaves as finger utility) that uses netcat this way and I need to know if the solution is good or not :-(
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Script server-finger.sh still runs and waits for requests from clients. It uses indefinite loop:
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while true ; do

echo "[Waiting for request]"
echo -n "" >"request.file"
nc -l -p 40017 >"request.file" # here it listens for requests

if [ -s "request.file" ]; then

# now we send information via netcat back

echo "[Sending output for request: $user]"
DO_SOME_STAFF >"output.file"
nc -w 1 "$remote_host" "$port"<"output.file"
echo "[Request ($user) was served.]"

fi
done


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Client script
===============================================

# retrieve IP address of this machine
thisMachine=$(echo `/sbin/ifconfig eth0 | grep "inet addr" | cut -d ":" -f 2 | cut -d " " -f 1`)
host=$(echo $1 | cut -d'@' -f 2)
port=40017
data="SOME DATA TO SEND"

# send data
echo "$data|$thisMachine" | nc -w 1 "$host" "$port"

exitCode=$?

if [ $exitCode -eq 0 ]; then

# wait for data
nc -l -p "$port" >"output.file";

fi